The long-term consequences of perinatal diet for weight gain and coping with stress and immune challenge We are what we ate (#177)

The nutritional environment in early life can be
crucial in influencing body weight and has important consequences for
metabolism and weight regulation throughout life. As such, overfeeding during
the early postnatal period can lead to increased early weight gain that
persists throughout the juvenile period and into adulthood. We have recent
evidence to suggest this early weight gain can contribute to changes in
hypothalamic-pituitary-adrenal (HPA) axis (stress) function, and to how animals
respond to an immune challenge. Thus, adult rats made obese by having been
suckled in small litters are more anxious and have exacerbated HPA axis
responses to stress compared with those from control litters. Neonatally
overfed rats also have exacerbated febrile and inflammatory responses to a
toll-like receptor 2/4-mediated immune challenge. Our findings suggest this
enhanced inflammatory response may be at least partially due to less efficient
HPA axis negative feedback. Thus, neonatally overfed rats have greater neuronal
activation in the paraventricular nucleus of the hypothalamus, the apex of the
HPA axis, in response to a challenge with the Gram negative bacterial mimetic,
lipopolysaccharide (LPS). They also have a prolonged rise in plasma
corticosterone after LPS compared with control rats. Obesity is now, sadly, a
significant problem for Australian children, with 25 % of children considered
overweight or obese. Our findings suggest that in addition to metabolic
sequelae, these children may be predisposed to developing stress-related disorders
and will be less able to combat bacterial infections. We are currently
investigating the changes that occur as a result of overfeeding in that early
post-natal period to HPA axis and immune function, and if we can reverse these
effects.